Originally posted by quanchi112
He was arrogant and the same pitiful rational applies to Sidious with Vader.
Not really, both scenes are entirely different.
Sidious was distracted with torturing Luke and given Vader limped over to stand next to him, he had zero reason to think Vader would betray him and he wasn't reading his thoughts either.
Snoke meanwhile had said as such that Kylo wouldn't betray him, while sitting on his throne and actively reading every thought and saying that nothing was hidden from him as he read his mind.
Now had Snoke not had done this and said that he was, the scene might be more believable. But it's not, not with the way it was set up.
How can one read one's mind in its entirety and yet still get shocked at the actions said person does? It makes zero sense.